BAGHDAD, Iraq (CNN) -- Two U.S. soldiers have been charged with the premeditated murders of three Iraqis killed in three separate incidents between April and June of this year, according to a U.S. military statement.

In addition to the murder charges, the two enlisted men are accused of trying to cover up the crimes, committed in Iskandariya, about 25 miles south of Baghdad, by planting weapons next to the Iraqis' bodies, the military said.

The soldiers are identified as Staff Sgt. Michael A. Hensley, of Candler, North Carolina, and Spc. Jorge G Sandoval, Jr., of Laredo, Texas.

Hensley was charged with three counts of premeditated murder, three counts of obstruction of justice and three counts of "wrongfully placing a weapon" next to a body. Hensley was arrested Thursday and taken to Kuwait to be held before the trial.

Sandoval faces one count of premeditated murder and one count of wrongfully placing a weapon next to a body. He was arrested Tuesday at his home in Texas and was also taken to Kuwait, the military said.

Both are assigned to the U.S. Army's 1st Battalion, 501 Infantry Regiment, 4th Brigade (Airborne), 25th Infantry Division, based at Fort Richardson, Alaska.

The military statement said the investigation into the killings began when fellow soldiers reported wrongdoing to military authorities.

Also, U.S.-led coalition forces killed about 26 people they described as "secret cell terrorists" and captured another 17 during raids in Baghdad's Sadr City Saturday morning, the U.S. military said -- an operation that brought an angry response from Iraq's prime minister.

The U.S. military said the raids, conducted in the pre-dawn hours in the densely populated Shiite slum, targeted terrorists tied to "Iranian terror networks," which the military said are responsible for helping the flow of lethal aid into Iraq.

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An Iraqi Interior Ministry official said local officials reported just seven people killed and that all of them were civilians.

Iraqi Prime Minister Nuri al-Maliki said the attacks were carried out without the proper approval.

"The government will demand an explanation from the multinational forces about what happened in Sadr City earlier today," said al-Maliki, who deplored what he characterized as attacks on civilians under the guise of "fighting terrorists and militias."

The government "absolutely rejects any military operation by the multinational forces all over the provinces and cities of Iraq without a previous permission or coordination with the commandership of the Iraqi forces," he said.

He also said that the government also "prohibits any Iraqi special forces to comply or implement any military operations without the permission and approval of the Iraqi leadership in the military." Those who disobey such directives will face charges, he said.

In other raids on Saturday, coalition forces detained 16 people described as "suspected terrorists" during operations targeting al Qaeda in Iraq leaders in Nineveh and Anbar provinces, the U.S. military said.

The military also announced Saturday that an insurgent killed in fighting Friday near the Anbar province city of Falluja has been identified as a high-level al Qaeda leader.

An Egyptian, who is believed to have fought for al Qaeda in Afghanistan five years ago before moving into Iraq, was killed during fighting east of Falluja Friday, the military said.

The military said the man worked directly for the military emir of al Qaeda in Iraq, and is associated with other al Qaeda in Iraq senior leaders.

One U.S. soldier was killed and three others were wounded in Baghdad on Friday by a powerful homemade bomb, the military said in a statement on Saturday, bringing the June toll to 100.

The period of April through June, which corresponds with the buildup of U.S. troops known as the "surge," has been the deadliest three-month stretch for U.S. troops since the Iraqi war began, with 104 American troops killed in April and 126 killed in May.

Since the war began in 2003, 3570 U.S. troops have been killed in Iraq. Seven civilian employees of the Defense Department have also been killed.

Also on Saturday: At least 15 civilians and police recruits were killed in Muqdadiya, Iraq, on Saturday when a suicide bomber detonated in the Diyala province town, the Iraqi Interior Ministry said.

Twelve people were wounded in the bombing that hit an outdoor market, near a police station.

A mass grave with 35 to 40 bodies in it was found on Friday south of the Anbar city of Falluja, the U.S. military said Saturday. The remains were bound and had gunshot wounds, the military said.

The military also said that the report earlier this week of 20 men beheaded in Iraq's Salman Pak area appears to be "completely false and fabricated by unknown sources."

The area is southeast of Baghdad, in one of the so-called Baghdad belts where U.S. and Iraqi troops have launched operations against insurgents.E-mail to a friend